Solve for $x$ and $y$ using substitution. ${x-y = 2}$ ${x = -4y+7}$
Since $x$ has already been solved for, substitute $-4y+7$ for $x$ in the first equation. ${(-4y+7)}{- y = 2}$ Simplify and solve for $y$ $-4y+7 - y = 2$ $-5y+7 = 2$ $-5y+7{-7} = 2{-7}$ $-5y = -5$ $\dfrac{-5y}{{-5}} = \dfrac{-5}{{-5}}$ ${y = 1}$ Now that you know ${y = 1}$ , plug it back into $\thinspace {x = -4y+7}\thinspace$ to find $x$ ${x = -4}{(1)}{ + 7}$ $x = -4 + 7$ ${x = 3}$ You can also plug ${y = 1}$ into $\thinspace {x-y = 2}\thinspace$ and get the same answer for $x$ : ${x - }{(1)}{= 2}$ ${x = 3}$